So I did a little more digging on their webpage, and now I think I've discovered that the mystery sender is none other than...
A beautiful handmade ornament with the initials "JK11" on the back.
In this cute little pastels box, no less! Adorable!
Isn't that precious?
I was not expecting any ornaments and I got no clues from the lack of return address. AND...to be honest I'm no good at secrets, so I did a little digging. My husband noticed the zip code on the front of the box and we pinned the location down. It still didn't give me any hints as to the sender. So then I googled "ARWB" as written on the front of the box and remembered that I had recently joined: